There is a reason why we don’t let the user making the synchronization twice
In fact, Kinomap lets the video maker doing the synchronization on his own. Once done, Kinomap has a post-processing check related to the incline (gradient).
That's why we don’t let the user changing the synchronization later on.
Also because we check with Strava to get the segments within the track and create a video section per segment (especially for running and cycling videos).